1. Filed of the Invention
The present invention relates to a memory card adaptor which enables a small memory card to be used in a card connector for a large memory card that is larger than the small memory card.
2. Description of the Prior Art
Conventionally, as a downsized version of an SD card (24×32×2.1 mm: length×width×thickness), a mini SD card (20×21.5×1.4 mm: length×width×thickness) 200 shown in FIGS. 12A, 12B, and 12C has been provided. In the rear face side of an end portion of the front side of the mini SD card 200 in the case where the mini SD card is inserted in the normal insertion posture (hereinafter, the front side in this case is referred to as “rear side”), eleven contacts 204a to 204k are juxtaposed in a direction (hereinafter, referred to as “lateral direction”) which is perpendicular to the longitudinal direction and the thickness direction. In the rear side of the mini SD card 200, a cut-away portion 201 is formed by cutting away one edge. A step portion 202 which is upward directed is formed in each of the right and left side edges of the surface side of the rear end portion of the mini SD card 200 in which the width is narrowed by the cut-away portion 201. The cut-away portion 201 cooperates with the step portions 202 to prevent erroneous insertion of the mini SD card 200 into a card connector in a posture other than the normal insertion posture (insertion in a posture where the front and rear relationship and the front and back relationship are inverted) from occurring. A locking cut-away 203 is disposed in each of the right and left sides of the surface of the mini SD card 200 in a wider portion which is in front of the cut-away portion 201, so that, when the mini SD card 200 is attached to the card connector, locking members of the card connector are engaged with the locking cut-aways 203, thereby preventing-the mini SD card 200 from dropping off. In the eleven contacts 204a to 204k of the mini SD card 200, the first to eleventh contacts 204a to 204k are sequentially arranged in a direction from left to right as seen from the side of the rear face, four or the first, second, tenth, and eleventh contacts 204a, 204b, 204j, 204k are used for data, the third contact 204c is used for a command, two or the fourth and ninth contacts 204d, 204i are used for grounding, the seventh contact 204g is used for power supply, and the eighth contact 204h is used for a clock signal. The two or the fifth and sixth contacts 204e, 204f are preliminarily added to the mini SD card 200. The effective contacts are nine so as to correspond to the nine contacts of the SD card.
As a memory card which is smaller than the mini SD card 200, a TransFlash card, and a micro SD card (11×15×1 mm: length×width×thickness) 300 shown in FIGS. 13A, 13B, and 13C in which the TransFlash specification is adopted have been provided. In the rear face side of an end portion of the front side of the micro SD card 300 in the case where the micro SD card is inserted in the normal insertion posture (hereinafter, the front side in this case is referred to as “rear side”), eight contacts 303a to 303h are juxtaposed in a direction (hereinafter, referred to as “lateral direction”) which is perpendicular to the longitudinal direction and the thickness direction. In the rear side of the micro SD card 300, a cut-away portion 301 for preventing erroneous insertion is formed by cutting away one edge. A locking cut-away 302 is disposed in one side portion of the micro SD card 300 on the side of the cut-away portion 301 and in a wider portion which is in front of the cut-away portion 301. In the eight contacts 303a to 303h of the micro SD card 300, the first to eighth contacts 303a to 303h are sequentially arranged in a direction from left to right as seen from the side of the rear face, four or the first, second, seventh, and eighth contacts 303a, 303b, 303g, 303h are used for data, the third contact 303c is used for a command, the fourth contact 303d is used for power supply, the fifth contact 303e is used for a clock signal, and the sixth contact 303f is used for grounding. In the micro SD card 300, namely, the grounding contact is reduced to one, and the number of contacts is reduced to eight as compared with the case where an SD card and the mini SD card 200 have the nine contacts (in the mini SD card 200, the number of effective contacts).
As described above, miniaturization of memory cards is advancing. In order to enable a small memory card to be used in a card connector for a large memory card that is larger than the small memory card, a memory card adaptor for this purpose is required. In such an adaptor, the adaptor body is inevitably formed so as to have a shape corresponding to the outer shape of the large memory card. Memory cards are originally thin. As a result of miniaturization, the longitudinal and lateral dimensions are considerably reduced, but a large difference is not produced in thickness. Therefore, an outer peripheral portion (front and rear faces) of a housing space for a small memory card is thinned, and as a result there arises a problem in that it is difficult to maintain rigidity.
In order to solve the problem, a conventional memory card adaptor is often formed so that a rear face side (the side of the face where internal contacts are exposed in one end portion) of the adaptor body is configured by a resin base, and a metal cover is used in a thin portion of the surface side (for example, see Japanese Patent Application Laying-Open No. 2005-50280).